It's not clear who wrote the $237,000 check, and it's unusual for a presidential candidate's spouse to be paid for speaking during a campaign. And at least one ethics expert is calling the former first lady "self-serving.

Melania’s appearance at multiple Log Cabin Republicans events is notable, because she almost never campaigns on behalf of her 78-year-old hubby. This year, she attended a fundraiser with Trump in Palm Beach at the home of billionaire investor John Paulson and appeared briefly at the RNC without a speaking role.

Melania Trump received a payment of nearly $240,000 for a single speech during a fundraiser for an organization affiliated with the Republican Party, according to Donald Trump's financial report obtained by CNN.